Yeah, it's just a high pps application. Every cisco I've used under this kind of stress takes a beating. I have learned that Cisco's numbers are more marketing hype than gospel. It's been a while, but about the hardest running router I've spent any real time exploring/abusing was a pair of 6500 MSFC2s in HA. (sans crypto)
I ran a PIX515E (quad FE, crypto accelerator (broadcom, not the safexcel)) and it did not stand up well either under much of the same load. The max I was ever able to really pull through on the PIX (6.3(4) - never tried the 7 series releases) was about 30k pps (15k both ways) before it would start to get wonky (random reboots, probably not more than 3-4kpps of crypto). Of course, it really is only 433MHz i586 running a modified Plan9 Unix, so I wasn't expecting great things. It got replaced by a 3750 catalyst on the edge with OpenBSD firewalls for critical services that did not necessitate high pps rates. The 3750 is running full-tilt, but never sees any real duty. Excepting that it doesn't have any security features other than ACLs (and the usual myriad of tricks 😉), it has serious potential. Perhaps the 3750-metro version would do better, but I suspect there would be performance tradeoffs; besides, I'm 'comfortable' with the setup as it stands (offers redundancy, dynamic routing, PBR, extremely good performance). The 3825 was only brought into the mix for other various services and it is a nice device (these have come a LONG way since the old 3600 builds (RIP)), but I still wouldn't recommend them for hard-core crypto usage (> 100kpps) under any circumstance.
I'm getting ready to do some benchmarking on some old Nokia IP330s, sans crypto accelerator, to see how they stack up with Open/Free/NetBSD (rather than the CPFW1 IPSO that Nokia provides), should be interesting.
I guess the bottom line is that while I can make almost any Cisco dance up and down the street at my whim, I'm not about to succomb to their marketing juggernaut. Does it mean I won't buy their units? Nah.. they serve a specific purpose -- but I won't buy them with impunity. 😀